Electronic component, mounting structure thereof, and method for mounting electronic component

ABSTRACT

An electronic component includes: a functional piece having a predetermined function; a bump electrode formed on the functional piece, the bump electrode including a core with elastic property and a conductive film provided on a surface of the core; and a holding unit for holding a conductive contact state between the bump electrode and a connecting electrode which is electrically conducted to a driving circuit. The electronic component is coupled to the connecting electrode, and elastic deformation of the core causes the conductive film to make conductive contact with the connecting electrode.

BACKGROUND

1. Technical Field

The present invention relates to an electronic component such as aquartz crystal resonator, and a mounting structure thereof, as well asto a method for mounting the electronic component.

2. Related Art

In packages that include piezoelectric devices (electronic components)such as quartz crystal resonators, excitation electrodes provided to thequartz crystal resonators are fixed to connecting electrodes forcoupling driving circuits that drive the quartz crystal resonators, soas to make conductive contact between the excitation electrodes andcontact electrodes via a conductive paste such as solder (refer toJP-A-11-261360 for an example).

Such quartz crystal resonators however include the following problems.The contact area between the excitation electrodes and the connectingelectrodes decreases if concaves and convexes are provided on thesurface of the connecting electrodes. Moreover, the connectionreliability between the quartz crystal resonators and the connectingelectrodes needs to improve in order for the packages to cope withimpacts such as a drop impact.

SUMMARY

An advantage of the invention is to provide an electronic component thatimproves the connection reliability between the electronic component andthe connecting electrode, and a mounting structure of the electroniccomponent, as well as a method for mounting the electronic component.

In order to solve the above problems, aspects of the invention areprovided as follows. According to a first aspect of the invention, anelectronic component includes: a functional piece having a predeterminedfunction; a bump electrode formed on the functional piece, the bumpelectrode including a core with elastic property and a conductive filmprovided on a surface of the core; and a holding unit for holding aconductive contact state between the bump electrode and a connectingelectrode which is electrically conducted to a driving circuit. Theelectronic component is coupled to the connecting electrode, and elasticdeformation of the core causes the conductive film to make conductivecontact with the connecting electrode.

In this aspect, even if the connecting electrode has convexes, theelastic deformation of the core achieves a desirable conductive contactbetween the conductive film and the connecting electrode with asufficient contact area. Further, the holding unit holds the conductivecontact between the conductive film and the connecting electrode,thereby providing a high connection reliability therebetween.

In other words, when the bump electrode is pressed against theconnecting electrode during the mounting of the electronic component,the core elastically deforms so as to follow the surface shape of theconnecting electrode. This causes the conductive film formed on thesurface of the core to deform as well, following the surface shape ofthe connecting electrode. Consequently, the contact area of theconductive film and the connecting electrode increases, and the contactstate therebetween is held by the holding unit, thereby improving theirconnection reliability. Here, even if a contact position between thebump electrode and the connection electrode receives impacts, suchimpacts are absorbed by the elastic deformation of the bump electrode.This provides high impact resistance at the contact position of the bumpelectrode and the connecting electrode.

Moreover, forming the holding unit and the bump electrode with adifferent material allows for selecting the optimal material for each.Thus, high connection reliability is obtained between the bump electrodeand the connecting electrode.

In this case, supporting the functional piece in cantilever fashion maysuitably be employed.

Since only one side is constrained in the above structure, themechanical freedom of the functional piece increases, allowing to keepthe energy loss such as leak and vibration loss to a minimum.

It is preferable that the functional piece be supported in cantileverfashion in a vicinity of a conductive contact region between theconductive film and the connecting electrode.

Even if the thermal expansion coefficient of the functional piecediffers from that of members such as a substrate that includes theconnecting electrode, this one side coupling transmits less thermalstress to the connecting unit and to the quartz crystal piece, comparedto surface coupling or double-end coupling. Therefore, the connectionlifetime is extended, and the reliability of the electronic componentincreases, while preventing the generation of unwanted heat stress inthe members such as the substrate. Further, it is possible to reduce theeffect of the stress caused by the mechanical or thermal deformation tobe transmitted to the functional piece through the connecting unit.

It is preferable that the functional piece be supported in cantileverfashion at a node of vibration.

Consequently, the vibration of the functional piece does not attenuateat a support, and Q-factor (converting efficiency) ofelectric-mechanical vibration is improved.

In this case, the functional piece may constitute a piezoelectric devicewhich is displaced by energizing the conductive film.

Moreover, the functional piece may be a quartz crystal piece.

In this case, the quartz crystal piece used as the functional piececonstitutes a quartz crystal resonator.

Further, the holding unit may be an adhesive layer.

Adhering the conductive film and the connecting electrode with theadhesive layer holds the conductive contact therebetween.

Still further, the adhesive layer may cover the conductive film.

Here, when the bump electrode is pressed against the connectingelectrode during the mounting of the electronic component, the adhesivelayer is pushed out so that the conductive film makes conductive contactwith the connecting electrode.

It is preferable that part of the conductive film be exposed out of theadhesive layer.

At this time, the conductive layer is exposed out of the conductive filmso that the conductive film easily makes conductive contact with theconnecting electrode, without pushing the adhesive layer. Therefore, theconnection reliability of the conductive film and the connectingelectrode further improves.

It is preferable that the adhesive layer be spaced from the conductivefilm.

Here, since the adhesive layer is spaced from the conductive film, theconductive film easily makes, similar to the above, conductive contactwith the connecting electrode when the bump electrode is pressed againstthe connecting electrode during the mounting of the electroniccomponent. Therefore, the connection reliability of the conductive filmand the connecting electrode further improves.

According to a second aspect of the invention, a mounting structure ofan electronic component includes the electronic component describedabove and a substrate having the connecting electrode. In the structure,the electronic component is mounted on the substrate.

According to a third aspect of the invention, a method for mounting anelectronic component includes mounting the electronic componentdescribed above to a substrate having the connecting electrode.

This provides high impact resistance at the contact position of the bumpelectrode and the connecting electrode. Forming the holding unit and thebump electrode with a different material allows for selecting theoptimal material for each, thereby achieving high connection reliabilityof the bump electrode and the connection electrode. Moreover, supportingthe functional piece in cantilever fashion increases the mechanicalfreedom of the functional piece, keeping the energy loss such as leakand vibration loss to a minimum. At the same time, the connectionlifetime is extended, and the reliability of the electronic componentimproves, while the generation of unwanted heat stress is prevented inmembers such as a substrate, thereby reducing the effect of stress whichis caused by mechanical deformation and heat deformation to betransmitted to the functional piece through the connecting unit.

The electronic component according to aspects of the invention realizesa predetermined function by the electromagnetic effect, and includes apiezoelectric device and a magnetostrictive device, displacement thereofsuch as a vibration being generated from the effect of electric power ormagnetic power respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a sectional view illustrating a package of a quartz crystalresonator according to one embodiment.

FIG. 2 is a plan view of FIG. 1.

FIG. 3 is a perspective view illustrating the quartz crystal resonator.

FIGS. 4A and 4B are process charts showing a mounting method of thequartz crystal resonator.

FIG. 5 is a perspective view illustrating a mobile phone including thequartz crystal resonator.

FIG. 6 is a perspective view illustrating a quartz crystal resonatoraccording to another embodiment.

FIGS. 7A and 7B are process charts showing a mounting method of thequartz crystal resonator.

FIG. 8 is a perspective view illustrating a quartz crystal resonatoraccording to still another embodiment.

FIGS. 9A and 9B are process charts showing a mounting method of thequartz crystal resonator.

DESCRIPTION OF EXEMPLARY EMBODIMENTS First Embodiment

A first embodiment of an electronic component according to aspects ofthe invention will now be described based on drawings. The followingfigures used in the descriptions below have different scale sizesmodified for each of the components, so that each of them will besufficiently large to be recognized. Here, FIG. 1 is a sectional viewillustrating a quartz crystal resonator package that includes a quartzcrystal resonator. FIG. 2 is a plan view of FIG. 1, and FIG. 3 is aperspective view illustrating the quartz crystal resonator.

A quartz crystal resonator package 2 including a quartz crystalresonator (piezoelectric device) 1 as an electronic component accordingto aspects of the invention will now be described. The quartz crystalresonator package 2 includes, as illustrated in FIGS. 1 and 2, thequartz crystal resonator 1 and a housing 3 for sealing the quartzcrystal resonator 1.

As shown in FIGS. 1 to 3, the quartz crystal resonator 1 includes aquartz crystal piece (functional piece) 11, a pair of excitationelectrodes 12 and 13 for exciting the quartz crystal piece 11, a bumpelectrode 14, and an adhesive layer (holding unit) 15.

The quartz crystal piece 11 is a plate member which is U-shaped in planview, and has a planar shape of turning fork in which two arms 22 and 23extends from a base 21 in the same direction in parallel.

The pair of excitation electrodes 12 and 13 is formed with, forinstance, a conductive material such as aluminum (Al), and is formed onone side of the quartz crystal piece 11. The excitation electrode 12 isformed, extending from the base 21 to the arm 22, on one side (in FIG.1, the bottom surface) of the quartz crystal piece 11. The excitationelectrode 13 is formed, extending from the base 21 to the arm 23, on oneside of the quartz crystal piece 11.

The bump electrode 14 is formed on one side of the base 21. As shown inFIGS. 1 to 3, the bump electrode 14 includes a resin core (core) 24 anda pair of conductive films 25 and 26 formed on a surface of the resincore 24.

The resin core 24 is formed with photosensitive resin or thermosettingresin such as polyimide, acrylic, phenol, silicone, silicone-modifiedpolyimide, and epoxy resins.

As shown in FIG. 3, the resin core 24 is, prior to mounting the quartzcrystal resonator 1 to a housing body 31, formed approximately like abarrel vault and extends on one side of the base 21, in a directionapproximately orthogonal to the direction in which the pair of arms 22and 23 extends. Here, the “approximately a barrel vault shape” means acolumnar shape in which the inner (bottom) surface that is in contactwith the quartz crystal piece 11 is flat, and the outer surface that isnot in contact therewith is curved. Examples of a cross-section surfaceof such a shape include approximately a half circle, approximately ahalf oval, and approximately a trapezoid.

After mounting the quartz crystal resonator 1 to the housing body 31,the quartz crystal resonator 1 pressing relative to the housing body 31causes the resin core 24 to elastically deform, as shown in FIG. 1,following the surface shapes of connecting electrodes 33 and 34described later.

Here, the resin core 24 is formed with techniques such asphotolithography and etching, and the material (hardness) of the resincore 24 is optionally selected and designed in accordance withconditions such as the shapes of the connecting electrodes 33 and 34.

As shown in FIG. 3, the pair of conductive films 25 and 26 are formed onthe surface of the resin core 24, with a space interposed therebetween.The pair of conductive films 25 and 26 is made of metals and alloys suchas gold (Au), titanium tungsten (TiW), copper (Cu), chromium (Cr),nickel (Ni), Ti, W, nickel vanadium (NiV), Al, palladium (Pd), andlead-free solder, and may be either a single layer or a multilayer ofthese metals or alloys.

The conductive film 25 is formed continuously to the excitationelectrode 12, so as to be electrically conducted thereto. As shown inFIG. 1, after mounting the quartz crystal resonator 1 to the housingbody 31, the conductive film 25 deforms to follow the surface shape ofthe connecting electrode 33 due to the elastic deformation of the resincore 24, thereby making conductive contact with the connecting electrode33.

The conductive film 26 is formed continuously to the excitationelectrode 13, so as to be electrically conducted thereto. Moreover,after mounting the quartz crystal resonator 1 to the housing body 31,the conductive film 26 deforms to follow the surface shape of connectingelectrode 34 due to the elastic deformation of the resin core 24,thereby making conductive contact with the connecting electrode 34.

Here, the conductive films 25 and 26 are patterned after the filmdeposition with, for instance, sputtering. Alternatively, the conductivefilms 25 and 26 may also be formed by forming an underlying film withmethods such as sputtering and electroless plating and thereafterdepositing an upper layer film with electroplating. Similar to the resincore 24, the material (hardness) of the conductive films 25 and 26 areoptionally selected and designed in accordance with conditions such asthe shapes of the connecting electrodes 33 and 34. However, it ispreferable that the conductive films 25 and 26 be formed with Au thatexcels particularly in flatting property, since the resin core 24elastically deforms to follow the shape of the connecting electrodes 33and 34. Here, if the conductive films 25 and 26 have a multilayerstructure, it is preferable that the outermost layer be formed with Au.

The adhesive layer 15 is formed with adhesives such as epoxy resin andacrylic resin as shown in FIGS. 1 to 3. The adhesive layer 15 surroundsthe contact region of the conductive film 25 and the connectingelectrode 33, as well as the contact region of the conductive film 26and the connecting electrode 34. Moreover, prior to mounting the quartzcrystal resonator 1 to the housing body 31, the adhesive layer 15 iscoated so as to cover the surfaces of the conductive films 25 and 26, asshown in FIG. 3.

As shown in FIGS. 1 and 2, the quartz crystal resonator 1 (the quartzcrystal piece 11) is supported to the housing 3 in a cantileverstructure, only at the base 21 in a vicinity of the conductive contactregions (at the left side edge of the quartz crystal resonator 1 inFIGS. 1 and 2) in which the conductive films 25 and 26 makes conductivecontact with the connecting electrodes 33 and 34.

In other words, based on the vibration characteristics of the quartzcrystal piece 11, the conductive contact region is provided as acantilever support in the quartz crystal resonator 1, at a node ofvibration with the smallest amplitude during the vibration of the quartzcrystal piece 11.

The housing 3 includes the housing body 31 and a lid 32 that covers thehousing body 31.

The housing body 31 is formed approximately in a shape of a box, and ismade of an insulating material such as ceramics. The connectingelectrodes 33 and 34 are formed on the top surface of the bottom of thehousing body 31. Terminal electrodes 35 and 36 that are to be mounted onan un-illustrated circuit board are formed on the back surface of thebottom of the housing body 31.

The connecting electrodes 33 and 34 are formed with conductive materialssuch as metals, in a structure of, for instance, Au film deposited on aNi plated layer formed on a W film, and are coupled to the terminalelectrodes 35 and 36 through an un-illustrated wiring formed on thehousing body 31.

Similar to the housing body 31, the lid 32 is formed with an insulatingmaterial such as ceramics. The lid 32 is bonded to an opening of thehousing body 31 with methods such as soldering, so as to seal the quartzcrystal resonator 1 in a space formed between the housing body 31 andthe lid 32.

A method for mounting the quartz crystal resonator 1 will now bedescribed with reference to FIGS. 4A and 4B. FIGS. 4A and 4B aresectional drawings illustrating the bump electrode 14 during themounting of the quartz crystal resonator 1 to the housing body 31.

The bump electrode 14 installed on the quartz crystal resonator 1 isfirst made contact with and pressed to the connecting electrodes 33 and34 formed on the housing body 31 (FIGS. 4A and 4B).

At this time, the resin core 24 elastically deforms and follows theshapes of the connecting electrodes 33 and 34.

The conductive film 25 then follows the surface shape of the connectingelectrode 33 as the resin core 24 elastically deforms, and at the sametime, the conductive film 26 also follows the surface shape of theconnecting electrode 34. Thereafter, the adhesive layer 15 covering theconductive films 25 and 26 are pushed out along the outer surface of theresin core 24. Therefore, at least part of each of the conductive films25 and 26 covered by the adhesive layer 15 is exposed out of theadhesive layer 15, and contacts the connecting electrodes 33 or 34.Consequently, the conductive films 25 and 26 make conductive contactwith the connecting electrodes 33 and 34 with a sufficient contact area.

The adhesive layer 15 adheres the bump electrode 14 to the connectingelectrodes 33 and 34, and the conductive contact state is held betweenthe conductive film 25 and the connecting electrode 33, as well asbetween the conductive film 26 and the connecting electrode 34.

As described, the quartz crystal resonator 1 is mounted inside thehousing body 31. Thereafter, the quartz crystal resonator 1 is sealed bybonding the housing body 31 and the lid 32 together. As a result, thequartz crystal resonator package 2 is formed.

Here, if the connecting unit of the quartz crystal resonator 1 andhousing body 31 receives impact such as drop impact, the resin core 24absorbs the impact by elastic deformation.

Moreover, the quartz crystal piece 11 of the quartz crystal resonator 1is supported in a cantilever fashion at one place in the vicinity of theconductive contact regions in which the conductive films 25 and 26 makeconductive contact with the connecting electrodes 33 and 34. Thus themechanical freedom of the quartz crystal piece 11 increases at its end,allowing to keep the energy loss such as leak and vibration loss to aminimum. The quartz crystal resonator 1 is coupled with the housing body31 only at one side. Thus, compared to surface coupling or double-endcoupling, less thermal stress is transmitted to the connecting unit andto the quartz crystal piece 11, even if the thermal expansioncoefficient of the quartz crystal resonator 1 (quartz crystal piece 11)differs from that of members such as the ones including the connectingelectrodes 33 and 34. Therefore, the connection lifetime is extended,and the reliability of the electronic component increases, whilepreventing the generation of redundant heat stress in the members suchas a substrate. Further, it is possible to reduce the effect of thestress caused by the mechanical or thermal deformation to be transmittedto the quartz crystal piece 11 through the connecting unit.

Moreover, the quartz crystal resonator 1 is supported in cantileverfashion at a node of vibration of the quartz crystal piece 11. Thisallows for suppressing the vibration attenuation at a support of thequartz crystal piece 11, as well as for improving Q-factor (convertingefficiency) of electric-mechanical vibration.

Electronic Apparatus

The quartz crystal resonator 1 is used, for instance, in a mobile phone100 shown in FIG. 5. Here, FIG. 5 is a perspective view illustration themobile phone 100.

This mobile phone 100 includes a display unit 101, a plurality ofoperation buttons 102, an earpiece 103, a mouthpiece 104, and a bodythat includes the display unit 101.

As described, according to the quartz crystal resonator 1 in the firstembodiment, the elastic deformation of the resin core 24 achievesdesirable conductive contact with sufficient contact areas between theconductive films 25 and 26 and the connecting electrodes 33 and 34. Thisconductive contact is held by the adhesive layer 15, and thus a highconnection reliability is obtained therebetween.

Moreover, according to the quartz crystal resonator 1 in thisembodiment, the mechanical freedom of the quartz crystal piece 11increases at its end, allowing to keep the energy loss such as leak andvibration loss to a minimum. At the same time, thermal stress is nottransmitted to the connecting unit nor to the quartz crystal piece 11,even if the thermal expansion coefficient of the quartz crystalresonator 1 (quartz crystal piece 11) differs from that of the membersincluding the connecting electrodes 33 and 34. Consequently, theconnection lifetime is extended and stability of the electroniccomponent improves. Further, this embodiment does not generate excessivethermal stress in other members such as a substrate, thereby reducingthe effect of the stress caused by the mechanical or thermal deformationto be transmitted to the quartz crystal piece 11 through the connectingunit.

Second Embodiment

A second embodiment of a quartz crystal resonator according to aspectsof the invention will now be described based on drawings. FIG. 6 is aperspective view illustrating the quartz crystal resonator before beingmounted on the housing body, and FIGS. 7A and 7B are sectional drawingsillustrating the bump electrode during the mounting of the quartzcrystal resonator to the housing body. In this embodiment, the shape ofthe adhesive layer is different from that of the first embodiment. Thisdifference will mainly be described, and elements described in the aboveembodiment are denoted by the same numerical symbols and descriptionsthereof are omitted.

In quartz crystal resonator 110 according to this embodiment, prior tomounting the quartz crystal resonator 110 to the housing body 31, topparts of the conductive films 25 and 26 are exposed out of the adhesivelayer 111 as shown in FIG. 6.

The bump electrode 14 installed on the quartz crystal resonator 110 ismade contact with and pressed to the connecting electrodes 33 and 34installed on the housing body 31 (FIGS. 7A and 7B).

At this time, the resin core 24 elastically deforms and follows theshapes of the connecting electrodes 33 and 34. The conductive film 25then follows the shape of the connecting electrode 33 as the resin core24 elastically deforms, and at the same time, the conductive film 26also follows the shape of the connecting electrode 34. Here, since partof each of the conductive films 25 and 26 is exposed out of the adhesivelayer 111, the conductive films 25 and 26 contact the connectingelectrodes 33 and 34 when the bump electrode 14 contacts the connectingelectrodes 33 and 34.

The adhesive layer 111 adheres the bump electrode 14 to the connectingelectrodes 33 and 34, and the conductive contact state is held betweenthe conductive film 25 and the connecting electrode 33, as well asbetween the conductive film 26 and the connecting electrode 34.Consequently, the quartz crystal resonator 110 is mounted inside thehousing body 31.

As described, while the quartz crystal resonator 110 of the secondembodiment works in a similar manner and exhibits similar effect as thatof the first embodiment, the connection reliability is further improvedbetween the conductive films 25 and the connecting electrode 33 as wellas between the conductive films 26 and the connecting electrode 34during the mounting, since part of each of the conductive films 25 and26 is exposed out of the adhesive layer 111 in advance.

Third Embodiment

A third embodiment of a quartz crystal resonator according to aspects ofthe invention will now be described based on drawings. FIG. 8 is aperspective view illustrating the quartz crystal resonator before beingmounted on the housing body, and FIGS. 9A and 9B are sectional drawingsillustrating the bump electrode during the mounting of the quartzcrystal resonator to the housing body. In this embodiment, the shape ofthe adhesive layer is different from that of the first embodiment, andthis difference will mainly be described. Elements described in theabove embodiments are denoted by the same numerical symbols and thedescriptions thereof are omitted.

Prior to mounting a quartz crystal resonator 120 in this embodiment tothe housing body 31, a pair of adhesive layers 121 is spaced from theconductive films 25 and 26 as shown in FIG. 8.

The pair of adhesive layers 121 is placed with the resin core 24interposed therebetween, and is aligned in the direction orthogonal tothe direction the resin core 24 extends, one on a side adjacent to thearms 22 and 23, and the other on a side spaced from the arms 22 and 23.The shape of each of the adhesive layers 121 is formed in a squarepillar, and extends along the resin core 24 at a position spaced fromthe peripheries of the conductive films 25 and 26.

The bump electrode 14 installed on the quartz crystal resonator 120 ismade contact with and pressed to the connecting electrodes 33 and 34installed on the housing body 31 (FIGS. 9A and 9B).

At this time, the resin core 24 elastically deforms and follows theshapes of the connecting electrodes 33 and 34. The conductive film 25then follows the shape of the connecting electrode 33 as the resin core24 elastically deforms, and at the same time, the conductive film 26also follows the shape of the connecting electrode 34. Here, theconductive films 25 and 26 are spaced from the adhesive layers 121 andthus contact the connecting electrodes 33 and 34 when the bump electrode14 contacts the connecting electrodes 33 and 34.

The adhesive layer 121 adheres the bump electrode 14 to the connectingelectrodes 33 and 34, and the conductive contact state is held betweenthe conductive film 25 and the connecting electrode 33, as well asbetween the conductive film 26 and the connecting electrode 34.Consequently, the quartz crystal resonator 120 is mounted inside thehousing body 31.

As described, the quartz crystal resonator 120 of the third embodimentalso works in a similar manner and exhibits similar effect as that ofthe second embodiment.

In this embodiment, each of the adhesive layers 121 needs to be providedin a position spaced from the conductive films 25 and 26, and may haveother shape such as a ring.

The present invention shall not be limited to the above-mentionedembodiments, and may allow various modifications without departing fromthe main scope of the present invention.

For instance, the shape of the resin core is not limited to a barrelvault, and may also be a trapezoid. Moreover, while one resin core isformed for two conductive films, two resin cores may be formedcorresponding to the two conductive films. At this time, the resin coremay take another shape such as a hemispheroid.

Further, the core may be formed with materials other than resinmaterial, as long as the material is elastic.

In this embodiment, while descriptions of these embodiments refers tothe usage of a turning fork quartz crystal resonator, the type of quartzcrystal resonator is not limited thereto, and may include other quartzcrystal resonators such as an AT-cut oscillator and a surface acousticwave (SAW) oscillator. Further, while the quartz crystal resonator isformed using quartz piece as a functional piece, a piezoelectric deviceother than the quartz crystal resonator may be formed using otherpiezoelectric materials.

Still further, in the above embodiments, an example of the electroniccomponent includes the piezoelectric device in which the displacement ofthe functional piece is caused by the electric power supplied. However,the electronic component is not limited thereto, and may include, forinstance, a magnetostrictive device in which the displacement of thefunctional piece is caused by the magnetic power.

Moreover, the structure of the quartz crystal resonator and thepiezoelectric device is not limited to a cantilever as described in theabove embodiments, and may include other structures such as surfacecoupling and doubly clamped structures.

In the above embodiments, while the description is made for the examplesin which quartz crystal resonator is mounted on the housing, the quartzcrystal resonator may be mounted on a substrate on which a wiringpattern is formed. As described, the quartz crystal resonator is mountedon the housing body with the adhesive layer being provided to the quartzcrystal resonator. Alternatively, the quartz crystal resonator may bemounted to the housing body in a state in which the adhesive layer isprovided to the container body or a substrate, not by forming the bumpelectrode and providing the adhesive layer on the quartz crystalresonator as described in the embodiments.

The electronic component and the mounting structure thereof as well asthe method for mounting the electronic component described in the aboveembodiments may be widely applied to micro-electro mechanical systems(MEMS) such as a mechanical component, a sensor, an actuator, and adevice in which electronic circuits are integrated into a single siliconsubstrate (an inkjet printer head, a pressure sensor, an accelerationsensor, and a gyroscope).

1. An electronic component, comprising: a functional piece having a predetermined function; a bump electrode formed on the functional piece, the bump electrode including: a core with elastic property; and a conductive film provided on a surface of the core; and a holding unit for holding a conductive contact state between the bump electrode and a connecting electrode which is electrically conducted to a driving circuit, wherein the electronic component is coupled to the connecting electrode, and elastic deformation of the core causes the conductive film to make conductive contact with the connecting electrode, wherein the functional piece is supported in cantilever fashion.
 2. The electronic component according to claim 1, wherein the functional piece is supported in cantilever fashion in a vicinity of a conductive contact region between the conductive film and the connecting electrode.
 3. The electronic component according to claim 1, wherein the functional piece is supported in cantilever fashion at a node of vibration.
 4. An electronic component, comprising: a functional piece having a predetermined function; a bump electrode formed on the functional piece, the bump electrode including: a core with elastic property; and a conductive film provided on a surface of the core; and a holding unit for holding a conductive contact state between the bump electrode and a connecting electrode which is electrically conducted to a driving circuit, wherein the electronic component is coupled to the connecting electrode, and elastic deformation of the core causes the conductive film to make conductive contact with the connecting electrode, wherein the functional piece constitutes a piezoelectric device which is displaced by energizing the conductive film.
 5. The electronic component according to claim 4, wherein the functional piece is a quartz crystal piece.
 6. The electronic component according to claim 1, wherein the holding unit is an adhesive layer.
 7. The electronic component according to claim 6, wherein the adhesive layer covers the conductive film.
 8. The electronic component according to claim 7, wherein part of the conductive film is exposed out of the adhesive layer.
 9. The electronic component according to claim 6, wherein the adhesive layer is spaced from the conductive film.
 10. A mounting structure of an electronic component, comprising: the electronic component according to claim 1; and a substrate having the connecting electrode, wherein the electronic component is mounted on the substrate.
 11. A method for mounting an electronic component coupled to a connecting electrode which is electrically conducted to a driving circuit, the method comprising mounting the electronic component according claim 1 to a substrate having the connecting electrode.
 12. The electronic component according to claim 4, wherein the holding unit is an adhesive layer.
 13. The electronic component according to claim 12, wherein the adhesive layer covers the conductive film.
 14. The electronic component according to claim 13, wherein part of the conductive film is exposed out of the adhesive layer.
 15. The electronic component according to claim 12, wherein the adhesive layer is spaced from the conductive film.
 16. A mounting structure of an electronic component, comprising: the electronic component according to claim 4; and a substrate having the connecting electrode, wherein the electronic component is mounted on the substrate.
 17. A method for mounting an electronic component coupled to a connecting electrode which is electrically conducted to a driving circuit, the method comprising mounting the electronic component according claim 4 to a substrate having the connecting electrode.
 18. The electrical component according to claim 4, wherein the functional piece is supported in cantilever fashion.
 19. The electronic component according to claim 4, wherein the functional piece is supported in cantilever fashion in a vicinity of a conductive contact region between the conductive film and the connecting electrode or the functional piece is supported in cantilever fashion at a node of vibration.
 20. The electronic component according to claim 1, wherein the functional piece constitutes a piezoelectric device which is displaced by energizing the conductive film. 